Slush molding can easily form complex-shaped products, provide uniform thickness, and achieve a good material yield, so that slush molding is widely used for forming of automobile interior trim articles or the like.
Soft polyvinyl chloride-based powders have been used for slush molding materials for years. However, a plasticizer having a temperature below the freezing point can impair the feel of the molded article, and a skin shrinkage occurs due to time-elapsing escape of the plasticizer, resulting in a greater dimensional change. For this reason, the use of polyurethane resin-based powders in place of the soft polyvinyl chloride-based powders has been variously studied.
There has been proposed, for example, a powder composition for slush molding contains core-shell particles having a core layer formed from a thermoplastic polyurethane resin and a shell layer formed from a polymer of a vinyl monomer which is made by mixing an aqueous dispersion of a vinyl monomer with an aqueous dispersion of a thermoplastic polyurethane and then polymerizing the vinyl monomer and a shell layer formed by a polymer of a vinyl monomer (see, for example, the following Patent Document 1).    Patent Document 1: Japanese Unexamined Patent Publication No. 2005-96432